Grinding mill



E. c. LOESCHE GRINDING MILL 5 Sheehs-Sheet Filed Dec. 30 92 In ven forEe/vsr Cu/ar 1055045 Nov. 17, 1931.

Nov. 17, 1931. E. c. LOESCHE 3 3 GRINDING MILL Filed Dec. 30 1926 5Sheets-Sheet 2 Inventor:

ERNST (0&7 LOESCH v ATTORNEY E. C. LOESCHE GRINDING MILL Nov. 17, 1931.

Filed Dec. 1926 5 Sheets-Sheet 5 Inventor: [Fe/v57 Cu/ejr LoEscHE & a

,4 TTOE/VE Y Nov. 17, 1931. E. c. LOESCHE 1,832,403

GRINDING MILL Filed 1926 5 Sheets-Sheet 4 Fly. 5.

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171 ven tor ff/YST Cu T LoEscHg:

Nov. 17, 1931. E. c. LOESCHE 1,832,403

GRINDING MILL Filed Dec. 30 1926 5 Sheets-Sheet 5 Inventor.-

I EENST Culfir LoEscHE Arro/e/vsy ticles being efiected Patented Nov,17, 1931 ERNST CUB-'1 IDESCHE, OF IBEBLIN-LA NKWITZ, GERMANY ammo m1.

Application 111a: December so, 1926, Serial no. 157,888,1111d in GermanyDecember a1, 1925.

. My invention relates to improvements in grinding-mills, such. as areused for grindmg varlous materials such as rock, ore, cement,--etc. Moreparticularly my invention f relates to mills comprising a rotarycontainer in the form of a shallow bowl or dish adapted to receive thematerial to be ground, rollers or balls pressed on the surface of thesaid container and adapted to crush the material, 9. and means forremoving the material which has been reduced to the desired degree of,fineness, such means consisting of a blower for producing a current ofair adapted to separate the fine particles from the coarse 15 particles,or a sieve. One of theobjects of 'theimprovements is to provide 'a millof this type which is effective in operation, and by means of which thematerial is ound within a comparatively short perlod of time. so Withthis object in view my invention consists in providing means forpractically continuously removing the material being ound from therotary container, separatmg the fine particles from the coarse particles, removing the fine particles and letting the coarse particles passto a point or points below said rotary container, wherefrom the coarseparticles are returned on the ,rotary container for being again ground.By thus rapidly removing the finer particles from the container theaction of the rollers or balls on the coarse particles is moreefiicient, so that grinding is rapidly completed. I

Other. objects of the improvements will appear from the followingdescription of. 4 the invention. a

Forthepurposeof explaining the invention several examples embodying thesame have been shown in the accompanying drawings, in which the samereference characters have been used in all the views to indicatecorresponding parts. In said drawings,

Fig. 1 is a sectional elevation showing my improved mi1l,the sepprationof thefine pary means of a current of air,

, Fig. 2 is'a similar sectional'elevation in which in addition to. theparts shown inFig. 1 means are provided for causing the our- 9, rentof-airto act 'on the coarse material be;

ing returned to the rotary container for sep arating therefrom anyresidue of fine material which might be left within the material afterthe first or main separating operation,

Fig. 3 is a sectional view taken-on the line 3-3 of Fig. 2, the rotarycontainer and the crushing rollers being omitted.

Figs. 4 and 5 are sectional elevations showing other modifications,

ig. 6 is a partial sectional elevation illustrating the operation of thescoops for returning the coarse material to the rotary container,

Fig. 7 is a top-plan view of the container shown in Fig. 6, I

Fig. 8 is a sectional elevation taken on the line 8-8 of Fig. 6, and v IFig. 9 shows cross-sections taken on the lines L-I, II--II and III-IIIof Fig, 8.

' In the example shown in Fi 1 my improved grinding mill consists 0% a,casing 1 having, at its side, an intake passage 2 or a current of air,and an outlet passage 3, the passage 2 being connected with a blower forproducing a current of air. To-the top end of a vvertical shaft 4mounted in bearings 5, 5 a container 6 in the form of a shallow bowl iskeyed, which container is located within the casing 1 and is ada ted tohe acted upon by crushmg rollers mounted on rockers 8, sprin f9 actingon the said rockers in a directlon or 'pressmg the rollers 7 on thesurface of the container 6. The shaft 4 is adapted to be rotated bysuitable gearing.

To show what may be done, bevelear whee 10 and pulleys 11 are provlded.ebottom of the casing 1 is provided with a chute 12 through which thecoarse material is removed for being returned to the top face of thecontainer, the said chute including a gate 13 fornormally closing thesame. In the operation of the apparatus the material to be ground isthrown on the oontainer 6 through the passage 3, and the con-' tainer 6is rapidl rotated by means ofthe gearing 10,11. y centrifugal action thematerial gradually moves outwardly and upwardly and in position forbeing acted upon by the rollers 7. Thereafter the partly ground materialincluding fine and coarse particles is thrown outwardly and away fromthe container 6 and into a current of air flowing from the passage 2,through the annular passage provided between the circumference of thecontainer 6 and the wall ofthe casing 1, and the passage 3. The velocityof the said current is such that the particles of the material whichhave been reduced to the desired degree of fineness are carried alongand removed from the mill, while the coarse particles fall downwardly inopposition to the said current of air and on the inclined walls orbottom of the casing 1, from whence they are delivered through the chute12. Suitable means are provided for returning the coarse particles tothe container 6.

It appears therefore that the material being ground is practicallycontinuously held in motion, and that the fine material is immediatelyremoved, so that there is only coarse material on the container 6, andthe crushing action of the rollers 7 is not hampered by the loosematerial. a

In Figs. 2 and 3 I have shown a modification in which the fine particlesare more thoroughly separated from the coarse material. As shown in thesaid figures, the mill comprises a cylindrical casing 15 divided by ahorizontal partition 16 into an upper chamber 17 and a lower chamber 18.Above the partition 16 an intake pipe 19 opens into the chamber 17, andat the top of the casing 15 an outlet pipe 20 opens into the same. Tothe top end of a vertical shaft 21 a container 22 in the form of ashallow bowl is keyed, and the said shaft is adapted to be rapidlyrotated by means of a bevel gearing 23 and a pulley 24. Through the sidewall of the casing 15 a chute 25 is passed into the chamber 17 throughwhich the material to be ground is delivered on the top face of thecontainer 22. The top face of the container 22 is engaged by crushingrollers 26 mounted on rockers 27 (one of each onl being shown) actedupon by springs 28. T e container 22 is smaller in diameter than thecasing 15, so that an annular passa e 29 is provided between the saidparts. elow the said passage conical and part1 nested frusto-conicalmembers 30 are provlded which are spaced from each other at theiradjacent bottom and top parts thus providing annular passages 31. Thecontainer 22 is provided with holes 32, and in continuation of the saidholes scoops 33 are fixed to thebottom of the container 22, the saidscoops extending forwardly in the direction of the rotary movement ofthe container 22 and being adapted, upon rotation of the container, toraise the material deposited on the inner portion of the partition 16.As appears from Fig. 3 the pipe 19 is disposed tangentially of thecasing 15.

In the operation of the apparatus the bowlshaped container 22 is rapidlyrotated, a

current of air is blown through the pipe 19,

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and the material is delivered on the top face of the container 22through the chute 25. By reason of the tangential direction of the pipe19 the current of air flows around the conical rings 30 and the passage29, so that it is operative all over the'circumference of the container22. A part of the air flows upwardly through the annular passage 29, ashas been indicated by the arrows w. The remainder of the current of airflows through the annular passages 31 and upwardly, as hasbeen indicatedby the arrows y. The material to be ground is delivered on the top faceof the container 22 through the chute 25, and it moves outwardly thereonby centrifugal action, so that it is exposed to the crushing action ofthe rollers 26. Thereafter the partly ground material is thrownoutwardly and into the passage 29, in which the fine particles arecarried away by the current of air, while the coarser particles falldownwardly and into the conical chamber included by the conical rings30. On the said conical rings the coarser particles slide downwardly andto the part near the hub of the container 22, and as the material dropsfrom one ring to the next one, it is exposed to the action of thecurrent of air flowing through the passa cs 31, which current of airseparates any e particles which might have been left within thematerial. The material collected at the bottom part of the conicalchamber included between the rings 30 and near the hub of the container22 is raised by the scoops 33 through the holes 32 and to the centralpart of the container 22, so that it is again subjected by centrifugalforce to the crushing action of the rollers 26, the said operation beingrepeated until the material has been reduced to the desired de cc offinenem. Thus, by causing -t e material to' move through a continuouscircuit from the top face of the container 22, the passage 29, the topfaces of the rings 30, the scoops 33, and the holes 32, any fineparticles are separated from the coarse particles, so that the crushingrollers 26 act only on coarse material.

In the examples so far described, the fine particles are separated fromthe material by a current of air. In Fig. 4 I have shown a modification,in which separation is efi'ecte'd by means of a sieve or sifter. Asshownin.

the said figure the grinding mill consists of a casing 36 containingasieve 37 having the form of a frustum of a cone. To

the vertical shaft 38 a container 39 in j the form of a shallow bowl iskeyed,

the bottom of the casing 36 a chute 44 extends downwardly and with itsbottom end into position for delivering the partly ound materiahinto atrough 45, from whlch the material is'thrown away from thecontainer 39,and it slides downwardly on the sieve 37. The fine particles of thematerial pass through the sieve and into the bottom part of the casing36, from which they are removed by the conveyors 48. The coarseparticles move through the chute 44 and into the trough 45, from whichthey are lifted by the elevator 46 and returned onto the container 39through the funnel 42.

The modification shown in Fig. 5 is similar to the one shown in Fig. 4,and the same letters of reference have been used to indicatecorresponding parts. But as distinguished from Fig. 4, the means forreturning the partly ground material to the top face of the container 39are in the form of scoops 50 forming the continuation of holes 51 madein the container 39.

The operation of the apparatus is substantially the same as thatdescribed with reference to Fig. 4. But the partly ground material isreturned on the top face of the container 39 by means of the scoops 50.

In Figs. 6 to 91 have shown the construetion of the scoops by means ofwhich the partly ground material is returned to the top face of therotary container. As shown,

' the said container 55 is keyed to a rotary shaft 56, and the bottom 57of the casing enclosing the container 55 is inclined downwardly andtowards the shaft 56, so that the partly ground material thrown beyondthe periphery of the container 55 collects near the axis of thecontainer 55. Below the holes 58 scoops 59 are screwed to the bottom ofthe'container, which scoops extend forwardly in the direction of therotation of the container 55, as is shown in Fig. 7 in which thedirection of the rotation-has been indicated by an arrow 2. Thecross-sections I--I, 11-11 and III-III shown in Fig. 9 clearly indicatethe form of the scoops.

While in describing the invention reference has been made to particularexamples embodying the same I wish it to be understood that my inventionis not limited, to

i the constructions shownin the drawings, and

he ground thereof, and means for removing that various changes may bemade in the general arrangement of the apparatus and the construction ofits parts without departing from the invention.

What I claim is 1. A grinding mill, comprising a casing, a rotarybowl-shaped container mounted within said casing and having a diametersmaller than that of the casing so as to pro"- vide' an annular passagearound the same, crushing rollers engagin the to face of said container,means 0 erative wit 'n said casing and around sai' container for searating the fine particles of the material tom the partly ground coarseparticles, means for causing the artly round coarse particles of themateriaFto col ect below said container near the axis thereof, saidcontainer being formed near its axis with holes, and means for returningthe coarse particles collected below the container through said holes tothe top face of the container.

2. A grinding mill, comprising a casing, a

rotary bowl-shaped container mounted within said casin and having adiameter smaller than that o the casing so as to provide an annularpassage around the same, crushing rollers engaging the top face of saidcontainer, means operative within said casing and around said containerfor se arating the fine particles of the material om the partly groundcoarse particles, means for causing the partly ground coarse articles ofthe material to collect below sai container near the axis thereof, saidcontainer being formed near its axis with holes, scoops fixed to thebottom side of said container and incontinua tion of the holes madetherein and extending forwardly and downwardly therefrom into positionfor elevating the coarse particles col ected below the container on thetop face the fine particles from the casing.

3. A grinding mill, comprising a cylindrical casing, a rotary bowl-sha dcontainermounted within said casing anfiaving a diameter" smaller thanthat of the casing so as to. provide an annular passage aroundthe same,crushing rollers engaging the top face of said container, means forproducing a current of air upwardly through 'said passage and means forreturning the coarse particles of material thrown from said container tothe top face and near the axis thereof.

rotary bowl-shaped container mounted within-said casing and having adiameter smaller than that of the casing so as to providezan" annularpassage around the same, crushing "conical member being in position forreceiv- 4. A grinding mill, comprising a casing, a 2 g 'ta1ner, andmeans for causmg a. current of air through said openings and upwardlytherefrom.

In testimony whereof I have aflixed my signature.

ERNST CURT LOESCHEZ

